Expansion percussion bit for drilling or boring operations



Sept. 36, 1924. 15%,222

\ J. H. HERMAN EXPANSION PERCUSSION-BIT FOR DRILLING OR BORINGOPERATIONS Filed July 9. 1920 s sheets-shear. l

H W WIN Sept. 30, 1924. 15161222 .J. H. HERMAN EXPANSION PERCUSSION BITFOR DRILLING OR BORING OPERATIONS rlled' duly 9. 1920 s Sheets-Sheet 2Sept; 30, 1924.. 11,510,222

J.H.HERMAN EXPANSION PERCUSSION BIT 'FO R DRILLING 0R BORING OPERATIONSFiled July 1920 3 Sheets-Sheet 5 Patented Sept. 30, 1924,

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J'O' HN' HENRY HERMAN, OF MELBOURNE, AUSTRALIA.

Application filed July 9,

To all whom it may concern: v

Be it known that I, JOHN HENRY HER- MAN, a citizen of the United Statesof America, and resident of Melbourne, Victoria, Australia, haveinvented certain'new and useful Improvements in Expansion PercussionBits for Drilling or Boring Operations, of which the following is adescription.

This invention relates to an improved under-reaming percussion bit fordrilling, or boring operations and refers especially to a bit for boringor drilling a hole of enlarged diameter in deep well operations such asoil or artesian bores.

In deep well bores as at present operated it is customary to drill for acertain distance with a hole of the same diameter as the inside of thecasing and to then withdraw the bit and use an under-reaming bit toenlarge the hole to the diameter of the outside of the casing so thatthe casing may be lowered to the extent of another length or section. 1

The object of this invention is to providea. drillin bit whereby a holeof the diameter of t e outside of the casing, may be drilled in the oneoperation thereby effecting 'a. great saving in time, labor and power.

I accomplish this object by providing a drilling bit having two cuttingedges one of which is located above the other and is arranged to cutaway the sides of the bore formed by the lower cutting edge and. apivoted trigger member adapted to bear against the sides of the borebelow the casing and cause the bit to operate eccentrically whereby theupper cutting edge will enlarge the diameter of the hole cut by thelower cutting edge of the bit.

In order that the invention may be readily understood reference will nowbehad to the accompanying sheets of explanatory draw-- ings wherein jFigure 1 is a viewin side elevation of a percussion bit constructed inaccordance with the present invention showing it in its raised positionand within the casing of a bore, part of the bore and easing beingbroken away for convenience of illustration.

Figure 2 is a view similar to Figure 1-.

. quite smoothly.

1920. Serial N0. 395,069.

showing the percussion bit at the bottom of its stroke and thrust to oneside of the bore.

Figure 3 is a. view in elevation of the percussion bit shown in Figures1 and 2 and 55 drawn to a. larger scale.

Figure 4 is a view in side elevation of the percussion bit showing partbroken away to clearly illustrate the pivoted trigger member and methodof attaching it to the bit.

' Figures 5 to 8 illustrate details in the construction of the triggermechanism and hereinafter will be fully described.

Figure 9 is a. view in inverted plan of the cutting edges of thepercussionbit shown in Figures 3 and 4. r

In these drawings the letter a designates the hit which is formed withthe screw shank Z; on the upper end set to one side of the centre andthe lower end oi. the bit 79 is provided with two cutting edges, anarrow central edge 0 and abroad lateral edge d one of which is disposedabove theother.

The lower cutting edge 0 extends from the side of the bit nearest theaxis of the screw shank to a point beyond the centre of the bit and isnarrower than the upper cutting edge (Z which extends from a point inline with the inner corner of the lower cutting edge a to the side ofthe bit farthest from 80 th'e'axis of the said bit.

lhe lower cutting edge 0 is adapted to form the well bore e and theupper cutter d is designed to cut to the outside diameter of the casingand thoroughly pulverize the material in the hole being formed (seeFigure 2 of the drawings). The part of the bit above the lower cuttingedge 0 1s made narrow to provide clearance for the' material cut away inthe drilling o eratlon ea and the upper cutting part is made roader andconforms to the shape of the periphery of the casing f to ensure thesides of the enlarged part of the bore being finished The side of thebit in line with and'at. a suitable distance above the lower cuttingedge a is formed with a recess 9 in which is pivoted a trigger member hwhichis normally pressed outward by means of a Spring 1% i. 'The triggermember is curved on its underside and the recess is so shaped that thetrigger member will move inwardly and outward y without leaving anopening through which dust and dirt can enter the said recess and sointerfere with the operation of the said trigger member. The upper endof the trigger member h is pivoted on a pin j passing through the upperend of the recess in the bit and the said member is shapedso that itwill swing outwardly beyond the side of the bit and inward into the saidrecess. An outward pressure is maintained on the trigger member h bymeans of the compression spring i which I exerts a thrust on a tappet ishaving one end ivotally connected to the said trigger mem er below thepivot point thereof.

The outer face of the trigger member can be fitted with a removable shoeh which can be readily removed when worn and replaced by a new one thusobviating the oxpense of fitting a new trigger member.

In order to ensure the bit passing freely into the 'top of the casing ina bore, the pivoted trigger member 71- is forced into the recess 9 untilit is flush with the side of the bit when the said bit may be passedfreely into and down through the casing (see Figure 1). When the bit haspassed through the casing the pivoted trigger member h is forced outwardby the action of the spring a and the shoe h thereon is caused to bearagainst the side of the enlarged part of the bore 6 as shown in Figure2. The

' pressure of the trigger member against the side of the bore causes thebit to be operated eccentrically whereby the upper cutting ed ge d willenlarge the diameter of the bore cut by the lower cutting edge a. lVhenthe bit is drawn upwardly prior to partially turuing and again droppingthe same the trigger member It will be forced into the recess when.

it strikes against the bottom of the casing.

The trigger member is moved outward by its spring directly the bitpasses through the basing on its next downward stroke and bears againstthe side of the well here farthest from the under reaming cutting edge dthereby causing the said cutting edge to bite into the side of the boreand enlarge the same.

The thrust of the trigger member against the side of the well borecauses the bit to operate more or less eccentrically accordingto thedistance to which the said trigger member is set to moveobeyond the sideof the recess in the bit, and-Tthe manner in which the bit is caused tooperate by. the

action of the said member as clearly shown in Figures 1 and 2 of thedrawings.

The trigger member bears against the side of the bore when the cuttingedges of the bit strike the bottom thereof and prevents any vibrationlikely to be set up in the bit and stem due to any side thruster cantingof the said bit when the broad cutting edge thereof strikes the oppositeside of the bore in performing the under-reaming operation.

The absence of vibration due to the above mentioned causes ensures thedrill working quite smoothly and prevents the stems or joints of thetools being subjected to undue stress or jar.

I claim: a

1. In a percussion bit for drilling and boring operations, a bit bodyhaving a lower narrow cutting edge and a second broader cutting edgespaced above the lower edge and offset laterally therefrom, said bitbody provided in one side adjacent to the narrow cutting edge with anarrow deep recess, a bearing member Inovably fitting within the recess,a pivot carried by the bit body and engaging through the upper endportion of said movable member and adapted to receive thrust thereofwhen extended, and a horizontally arranged spring seated in the body 2.A percussion bit for drilling or boring operations comprising anelongated bit body having longitudinally spaced apart cutting edges onits lower end with the upper-cutting edge offset laterallyoutward fromthe lower cutting edge, and a pressure member pivotally mounted in theside of said bit body adjacent to the lower cutting edge, said pressuremember having an arcuate outer edge adapted to lie closely to the innerwall of the bit body and to prevent accumulations of foreign substancesbeneath the member when open, and means for yieldingly urging saidpressure member outwardwhereby sald member is adapted to swing outwardlythrough the side of the bit body upon passage thereof beyond theextremity of a casing. I

3. A percussion bit for drilling and bormg operations comprising a bitbody provided at one side with relatively stepped cutting edges, asegmental ressure member pivoted within the other si e of said b1t bodyand in spaced gelation to said lower end thereof, a springttrrangedhorizontally in said bit body with one end thereagainst and its otherend against said segmental pressure member whereby to normally urge thelatter into an outward position, the pivotal axis of said pressure'memberbeing arranged substantially in the horizontal plane of the polntof contact between the pressure mem .er and the side of the well bore,whereby pressure position under pressure,

exerted against said ressure member is transmitted substantial y in astraight line to said pivotal axis for maintaining said segmental memberin an outwardly extending adapted to withstand shocks of ercussionineident to impacting said bit he y.

said spring being In testimony that I claim the foregoing as myinvention, I have signed my name in presence of two subscribinwitnesses.

" JOHN HENR HERMAN.

Witnesses:

01m A. HAon, G. R. GULLEN.

